Severe thyrotoxicosis at diagnosis is associated with a faster progression to hypothyroidism, highlighting the need for closer monitoring in these patients, while the presence of anti-Tg antibodies, reduced thyroid volume, and persistent hypoechoic areas on ultrasound provide additional clinical utility as predictors of long-term hypothyroidism, offering deeper insights into the pathophysiology of SAT. This evidence concerns the gene TG and hypothyroidism.